I visited this site (Echmiatsin, to be precise) twice during my stay in Armenia. The first time when fresh out of the plane, the second time after travelling around Armenia for a week. At first, I found the main cathedral a bit sober, but it's exuberant compared to others around the country.
Zvartnots is a completely different sight. In ruins and with snow-clad mountains in the background, it looks like a classic Greek temple in the Peloponnesos. Later I saw a reconstruction of what it could have looked like before demolition, and that was definitely more like a typical Armenian cathedral.
On my second visit, I also went to Surp Hripsime (shown in the big photo above): a 6th-century church about 2 km. from the main Echmiatsin complex. It's a bit big and bulky, but nice.